/**
 * Copyright (c) 2011-2017, James Zhan 詹波 (jfinal@126.com).
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.jfinal.template;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * FileStringSource
 */
public class FileStringSource implements IStringSource {
	
	private String finalFileName;  // 绝对path
	private String fileName;  // 文件名称
	private String encoding;  // 字符编码
	
	private long lastModified;  // 最后修改时间
	
	public FileStringSource(String baseTemplatePath, String fileName, String encoding) {
		this.finalFileName = buildFinalFileName( baseTemplatePath, fileName );
		this.fileName = fileName;
		this.encoding= encoding;
	}
	
	public FileStringSource(String baseTemplatePath, String fileName) {
		this( baseTemplatePath, fileName, EngineConfig.DEFAULT_ENCODING );
	}
	
	/**
	 * 判断文件是否被更改
	 */
	public boolean isModified() {
		return lastModified != new File(finalFileName).lastModified();
	}
	
	public String getKey() {
		return fileName;
	}
	
	public String getEncoding() {
		return encoding;
	}
	
	public String getFinalFileName() {
		return finalFileName;
	}
	
	public String getFileName() {
		return fileName;
	}
	
	/**
	 * 获取文件内容
	 */
	public StringBuilder getContent() {
		
		File file = new File(finalFileName);
		if (!file.exists()) {
			throw new RuntimeException("File not found : " + finalFileName);
		}
		
		// 极为重要，否则在模板文件被修改后会不断 reload 模板文件
		this.lastModified = file.lastModified();
		
		return loadFile( file, encoding );
	}
	
	/**
	 * 组装文件绝对path
	 * 
	 * @param baseTemplatePath
	 * 					template基础path
	 * @param fileName
	 * 					文件名
	 * @return
	 */
	private String buildFinalFileName(String baseTemplatePath, String fileName) {
		
		char firstChar = fileName.charAt(0);
		
		String finalFileName;
		if ( firstChar == '/' || firstChar == '\\' ) {
			finalFileName = baseTemplatePath + fileName;
		} else {
			finalFileName = baseTemplatePath + File.separator + fileName;
		}
		
		return finalFileName;
	}
	
	/**
	 * 加载读取文件内容
	 * 
	 * @param file
	 * 				文件
	 * @param encoding
	 * 				字符编码
	 * @return
	 */
	public static StringBuilder loadFile(File file, String encoding) {
		
		StringBuilder ret = new StringBuilder( (int)file.length() + 3 );
		
		BufferedReader br = null;
		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(file), encoding));
			// br = new BufferedReader(new FileReader(fileName));
			
			String line = br.readLine();
			if ( line != null ) {
				ret.append( line );
			} else {
				return ret;
			}
			
			while ( ( line=br.readLine() ) != null ) {
				ret.append( '\n' ).append( line );
			}
			
			return ret;
		} catch (Exception e) {
			throw new RuntimeException( e );
		}
		finally {
			if ( br != null ) {
				try {
					br.close();
				} catch (IOException e) {
					com.jfinal.kit.LogKit.error( e.getMessage(), e );
				}
			}
		}
	}
	
	public String toString() {
		
		StringBuilder sb = new StringBuilder();
		sb.append( "File name: " ).append( fileName ).append( "\n" );
		sb.append( "Final file name: " ).append( finalFileName ).append( "\n" );
		sb.append( "Last modified: " ).append( lastModified ).append( "\n" );
		
		return sb.toString();
	}
}




